Hashtags, retweets and in-tweet purchases? A new feature that temporarily popped up this week on Twitter's mobile app indicates the micro-blogging social network might be getting ready to step into e-commerce.

Earlier this week, a "Buy now" button appeared alongside tweets containing links to products sold through Fancy, an online shopping site, Recode reported; an unnamed source said that tapping on the button led users to a checkout page. The feature is no longer working.

The news might seem trivial by itself, but Twitter investors are looking for every sign that the company can boost dependable cash flow. Twitter relies on advertising for its revenue, but since going public in November, the San Francisco company has struggled to please investors. Right now, Twitter is trading around $42.30 per share, down from when it was trading higher than $70 per share in December. The social network may be interested in e-commerce as a way to create a second revenue stream.

This isn't the first time Twitter has dabbled with e-commerce.

In May, Twitter teamed up with Amazon.com to make it possible for users to add products to their Amazon shopping carts through tweets. To do so, users respond with "#AmazonCart" to tweets containing links to products from the online retailer.

If Twitter does add in-tweet purchases, it would follow another major social network in adding shopping to its platform. In 2012, Facebook added an e-commerce feature by making it possible for users to buy and send gifts to one another. Users can send gifts at any time, but on users' birthdays, Facebook highlights the feature to users' friends, suggesting that they send something.